Vaporproof luminaire



March 28, 1939.

T. W. ROLPH VAPORPROVOF LUMINAIRE Filed Deo. 17, f 1956 A TTORNEY Patented Mar. 28, 1935 UNITEDy STATES PATENT OFFICE vAPoRPRooF LUMINAmE Thomas W. Rolph, Newark, Ohio, assignor to Holophane Company, Inc., New York, N. Y., a corporation o! Delaware Application neeember 17, 193s, serial No. 116,295

1 claim. (ci. 24o- 93) The present invention relates to vapor-proof luminaires.

Vapor-proof luminaires are designed for use in locations wherein it is important to prevent the 5 entrance of explosive or corrosive vapors to the inside of the luminaire. It has been customary to employ simple blown glass enclosing globes with gas-tight fltters to receive the lamp socket and bulb. 'I'hese devices may also have an outer reflector to salvage some of the light transmitted upwardly by the plain glass globe.

The present invention contemplates the provision of vapor-proof luminaries in which the glass globe for the light source is provided with l5 annular light-depressing prisms, whereby the light emitted through the globe is transmitted at lowered angles. The litter and prismatic globe constitute a complete vapor-proof enclosure for the light source.

It is a further object of the present invention to enclose the prismatic globe in an annular prismatic reector, which receives the light transmitted by the globe and reflects it into further lowered angles. This reector is preferably closed by a diusing plate, which receives the joints between the globe, the reector and the plate, where these supplemental light-controlling devices are employed.

The accompanying drawing shows, for purposes of illustrating the present invention, several embodiments in which the invention may take form,

it being understood that the drawing is illustrative of the invention rather than limiting the same.

In this drawing:

Figure 1 is a vertical sectional view with parts in elevation, showing a vapor-proof luminaire having the external reector and plate, these parts being secured together by one form of construction; and

Figure 2 is a View similar to Figure 1, showing the reector and plate secured to the globe by a different form of construction.

In the arrangement shown in Figure 1, the tter 30 carries a lamp socket 3l and lamp bulb 32. The bottom of the litter is provided with a threaded side wall, indicated at 33, to receive the corresponding threads 34 on the upper end of the glass globe 35. This globe extends down about the sides of the lamp bulb, and underneath the lamp bulb, and the bottom of the globe is imperforate, so that when the globe is threaded against the gasket 36 a gas-tight chamber is provided.

The outer surface of the sidewall of the globe 35 is provided with horizontalprisms 31 which 5 extend up to an outer flange 38. The extreme lower end 39 of the globe 35 extends downwardly and ls provided with external threads 40 to receive a lock nut 4l. This lock nut bears against a glass plate 42, and the outer edge 43 of this plate 10 bears on the lower edge or mouth 44 of a prismatic glass reflector 45. The upper end 46 of the reflector 45 bears against a gasket or washer 4l interposed between it and the ange 38. Lugs 48 and 49 prevent relative rotation of the lower 15 plate 42 and the inner globe, and the parts are clamped so tightly together that they may be handled as a unit in threading the glass parts into and out of the fitter.

The outer reflector 45 is provided with in- 20 teriorly disposed annular reflecting prisms 50 which co-operate with the prisms carried by the inner globe to further lower the light rays. Typical light rays, such as 5l, 52 and 53, are retracted by the inner globe and then reflected by 25 the outer reflector and transmitted downwardly toward the bottom plate, as indicated at 5I', 52 and 53'. These light rays as well as lower rays 54 and 55 are received by the plate 42. As this plate is preferably provided with radial diffusing 30 flutes 56, the light is evenly diffused underneath the unit.

It will be noted that the outer surface of the luminaire is smooth, and that the prisms for light control are all enclosed, so as to be free from dirt 35 and dust, also that it is not necessary to provide gas-tight joints between the inner globe, the reilector, and the closure plate.

In the construction shown in Figure 2, the arrangement is optically substantially the same as 40 that shown in Figure 1, but the mechanical construction of the glass parts is somewhat diierent. 'I'he inner glass globe 60 is provided with an external ange 6I above the prisms, and the bottom of the globe is provided with a teat or pro- 45 jection 62.- The outer reflector 63 is received above the flange 6l. The lower plate 64 is secured to the bottom of the reflector 53 by clips, such as indicated at 65, and a coiled spring 66 interposed between the plate and bottom of the 50 globe holds the parts tightly in position. Relative rotation of the reector and globe may be obtained by interlocking the flange 6| and the upper inner end of the reector 63, as, for example, by lugs, indicated in dotted lines at 61. 55

Should one desire'a luminaire with a prismatic eector but without the lower diffusing plate, the orm shown in Figure 2 may be used, the reector hanging from` the ange 8| and held against rattling in any convenient manner.

It will be understood that the glass parts of Figures 1 and 2 may be secured to the tter by a bail instead of threading if desired, also the various other forms of securement of the parts to the fitter may be employed. it only being essential that the gas-tight joint be maintained.

It is apparent that, within the scope of the invention, modications and different arrangements may be made other than is herein disclosed, and the present disclosure is illustrative merely, the invention comprehending all variations thereof.

What is claimed is:

As an article of manufacture an enclosure adopted for use with a pendent light source carried by a vapor-proof fitter having a screw threaded skirt, said enclosure comprising a refractlng glass bowl adapted to receive the light source and having a closed bottom and substan tially vertically side walls provided with annular light depressing prisms, a threaded top adapted to nt the tter, and a ange below the threads, an outer annular glass ring engaging the flange and having downwardly and outwardly aring walls provided with reflecting prisms to reflect the retracted light downwardly through the mouth of the ring, a diffusing glass plate closing the bottom of the ring, and means to secure the 15 three pieces of glass together.

THOMAS W. ROLPH. 

